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DNA TECHNOLOGY (intro video)

DNA TECHNOLOGY (intro video). Chapter 16 karyotyping splicing and restriction enzymes gel electrophoresis cloning stem cells gene therapy microarrays. What is a Chromosome?.

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DNA TECHNOLOGY (intro video)

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  1. DNA TECHNOLOGY(intro video) • Chapter 16 • karyotyping splicing and restriction enzymes gel electrophoresis cloning stem cells gene therapy microarrays

  2. What is a Chromosome? Structure containing the DNA within a cellDna IS IN THE FORM OF CHROMATIN IN THE CELL MOST OF THE TIME (LOOSE FIBERS OF dna)Usually not visible until preps for replication – then becomes a replicated chromosome with 2 sister chromatids held by a centromere

  3. Chromosome Number in Humans • Number of chromosomes in cells? • 46 = 23 pairs for humans • 23 from mother/23 from father • AUTOMSOMAL chromosomes: 1-22 • SEX chrom.: 23rd pair (XX = female / XY = male) • DIPLOID – pairs of chromosomes/2n • 23 pairs – total 46 • HAPLOID – no pairs /n • 23 single

  4. 2 kinds of cells • Somatic or Body cells: 2n • Contain diploid # chromosomes • 2 sex chromosomes • Pairs of chromosomes • Sex Cells: egg or sperm 1n • Contain haploid # chromosomes • 1 sex chromosomes • No pairs of chromosomes

  5. Karyotype A picture taken through a microscope of a person’s genome ( chromosomes) organized in appearance according to size, shape, and bandingappearance. Visible replicated chromosomes Used for: Identifying gender Chromosomal abnormalities

  6. Original photo of nucleus

  7. Male and Female Karyotypes Male Female

  8. FYI - Chromosome 1 • Chromosome 1 contains nearly twice as many genes as the average chromosome and makes up 8%of the human genetic code. • It is packed with 3141 genesand linked to 350 illnesses including cancer, Alzheimer's and Parkinson's disease • The sequence of chromosome 1 took an international team of 150 scientists 10 yearsto complete.

  9. Nondisjunction • Failure of homologous chromosomes to separate properly during meiosis • Typical Abnormalities: • Trisomy • Gamete with an extra chromosome is fertilized by a normal gamete, the zygote will have an extra chromosome • Human-47 Chromosomes instead 46

  10. Extra chromosome #21

  11. Down Syndrome – most common 1. short stature 2. slanting fold of skin of the upper eyelids 3. susceptibility to leukemia and cataracts 4. subnormal mentality 5. shortened lifespan Chances increase with mother’s age. But, 23% of cases are due to father having an extra #21.

  12. Edward’sSyndrome-2nd most common nondisjunction disorder • trisomy of chromosome 18 • mental and motor retardation • serious health problems. • Ninety percent die in infancy; however, those who live past their first birthday usually are quite healthy thereafter. • They have a characteristic hand appearance with clenched hands and overlapping fingers.

  13. Other 3 copies of chromosomes: Three #18 Three #13 (Patau) Different symptoms at birth Both die within a few weeks

  14. Another example Triploidy Total lack of separation of homologous chromosomes Offspring with three sets of chromosomes Rare in animals, common in plants Nondisjunction

  15. Triploidy

  16. Abnormalities in Sex Chromosomes Remember: normal is XX or XY

  17. Turner Syndrome • Monosomy - 1 X chromosome (not XX or XY) • Female sexual characteristics are present but underdeveloped. • Sterile, short stature, low hairline, abnormal eye features and bone development and a "caved-in" appearance to the chest, heart defects

  18. Super Female – XXX, XXXX, XXXXX XXX – triple X syndrome Appearance: normal Looks like Turner individual Retardation Sterile XXXX, XXXXX – Tetra X and Penta X severely retarded

  19. Klinefelter’s Syndrome - XXY • Men are usually sterile, have longer arms and legs and are taller than their peers. • Boys with the syndrome are often shy and quiet, and have a higher incidence of speech delay and dyslexia.

  20. Jacob’s Syndrome - XYY Super male Taller than average Persistent acne Lower intelligence Criminal Syndrome – early claims incorrect?

  21. What is the diagnosis? Edward’s Syndrome

  22. What is the diagnosis? Kleinfelter’s (XXY) Syndrome

  23. What is the diagnosis? Turner Syndrome

  24. What is the diagnosis? Down Syndrome

  25. Genetic Engineering - • Manipulation and alteration of genes for practical purposes (use DNA technology) - identify genes for specific traits - transfer genes from one organism to another

  26. Terms to Know: • Recombinant DNA: DNA from 2 or more sources • Transgenic organism: host organism receiving recombinant DNA (example: transgenic bacteria can be put into growth medium to reproduce and make cloned insulin

  27. GENE SPLICING • Cutting DNA of a gene to add base pairs. • no sharp instruments are involved, restriction enzymes are used (like scissors) DNA ligase “glues the pieces together!!

  28. Restriction Enzymes • Bacterial enzymes are used to cut DNA molecules • Recognize specific sequences of nucleotides • Create “sticky ends” that can bind to complimentary chains of DNA • Used to cut DNA samples for DNA fingerprinting and cloning vectors

  29. DNA Fingerprinting-pattern of bands made from specific fragments from individual DNA • Compare banding fragments of two individuals • Compare two species to see how closely related • Use a statistical probability of a chance match between a suspect and biological evidence at a crime scene or in paternity cases • Depends upon the number of times a repeating pattern occurs Easier to exclude as a parent or convict as criminal

  30. DNA is found in …hair, semen, blood and other cells DNA Fingerprinting… 1st used in England for a paternity case in 1985 1st used in U.S. to convict criminals in 1987

  31. Accuracy • Complete sets of DNA are not compared • Only .1% of human genome varies from person to person (ID people by this DNA) • Useful for: person’s paternity, identifying human remains, tracing human origins, and providing evidence in a criminal case. • 98% of genetic makeup doesn’t code for proteins • Compare segments that vary the most from person to person (noncoding segments that repeat over and over)

  32. More uses for DNA Fingerprinting? Identify endangered and protected species as an aid to wildlife officials (could be used for prosecuting poachers) Detect bacteria and other organisms that may pollute air, water, soil, and food Match organ donors with recipients in transplant programs Determine pedigree for seed or livestock breeds Authenticate consumables such as caviar and wine

  33. The likelihood that any 2 people would share the same DNA profile is… 1 in a quintillion (18 0’s)

  34. How is a DNA fingerprint made? • 1) Restriction enzymes are added to the DNA sample to cut it up into smaller pieces or fragments

  35. How is a DNA fingerprint made? • 2) Fragments are pulled through a gel (by an electrical charge) and distribute according to the size of the fragment

  36. How is a DNA fingerprint made? • 3) An x-ray picture is taken of this distribution and then can be compared to other DNA samples

  37. How is a DNA Fingerprint made? • Different people have different restriction enzyme “cut sites” Resulting in different sized DNA fragments. Person 1 Person 2 Resulting in different band patterns on a gel

  38. Uses of….

  39. Video: Can We Live Forever?PBS 53 minutes

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